EAS: Considerations for HILIC Method Migration

Importance of the topic

Hydrophilic interaction chromatography (HILIC) is widely used in regulated laboratories for polar compound analysis. Ensuring reliable method transfer between different HPLC systems is critical for quality control, but unique aspects of HILIC separations—especially the choice of autosampler needle wash—can impact chromatographic performance and system suitability.

Aims and overview of the study

This work examines how varying needle wash solvent compositions affect the migration of a USP Cetirizine Hydrochloride assay and organic impurities monograph from one HILIC system to another. The goal was to identify wash conditions that maintain system suitability and consistent peak shapes across two different HPLC platforms.

Methodology and instrumentation used

The study used six needle wash solutions with acetonitrile:water ratios of 93:7, 80:20, 60:40, 40:60, 20:80, and 7:93. Both systems employed the same:

• Column: XBridge BEH HILIC, 130 Å, 5 µm, 4.6 × 250 mm
• Mobile phase: Acetonitrile, water, and 1 M sulfuric acid (93:6.6:0.4)
• Detector: UV at 230 nm
• Flow rate: 1 mL/min; injection volume: 10 µL; run time: 10 min

System 1 was a Waters Arc HPLC with a 2489 UV detector; System 2 was a vendor-supplied HPLC of different autosampler design. Each wash was flushed through the needle for six cycles before three replicate injections of a system suitability mix (4 µg/mL each of USP Cetirizine HCl RS and Related Compound A RS).

Key results and discussion

On the Arc HPLC system, all wash compositions yielded acceptable chromatography, meeting tailing (≤ 2.0) and resolution (≥ 2.0) criteria. In contrast, the Vendor X system exhibited significant peak splitting with more aqueous washes (20:80 and 7:93 acetonitrile:water), causing failure of suitability. A less aqueous wash (7:93) restored performance on the vendor system, demonstrating that residual strong solvent on the needle can disrupt HILIC separations depending on autosampler design.

Benefits and practical applications of the method

This study highlights the often-overlooked role of needle wash composition in method transfer and HILIC robustness. By optimizing wash solvents, laboratories can avoid troubleshooting column or sample preparation issues and ensure consistent results across different instruments.

Future trends and potential uses

• Development of standardized needle wash guidelines for HILIC monographs
• Improvements in autosampler cleaning mechanisms to minimize solvent carryover
• Integration of digital alerts to flag wash-induced chromatographic anomalies
• Extension of wash optimization strategies to other polar separation techniques

Conclusion

Needle wash solvent composition is a critical factor in migrating HILIC methods between systems. Tailoring the wash strength to the autosampler design ensures reliable chromatographic performance and reduces method transfer failures.

Reference

• Cetirizine Hydrochloride USPNF 2021 Issue 1 – online, USP43-NF38 – 910, USP42-NF37 – 891